Increasing utilization of neoadjuvant chemotherapy for stage IVB endometrial cancer (464)

Abstract

Objectives: The role of neoadjuvant chemotherapy (NACT) in advanced endometrial cancer is currently under active investigation. This study examined the trends, characteristics, and outcomes of women with stage IVB endometrial cancer who received NACT prior to hysterectomy. Methods: This retrospective observational study queried the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program. The study population included 5,505 women with stage IVB endometrial cancer from 2010-2018. The exposure allocation was per treatment approach: primary hysterectomy followed by chemotherapy (n=3,052, 55.4%), NACT followed by hysterectomy (n=930, 16.9%), and chemotherapy alone without hysterectomy (n=1,523, 27.7%). The main outcome measures were (i) trend of utilization and patient characteristics related to NACT assessed with multinomial regression analysis and (ii) all-cause mortality per treatment approach assessed with multivariable Cox proportional hazards regression model. Results: Sites of distant organ metastasis included lung (23.9%), liver (11.9%), bone (7.6%), and brain (1.8%). The number of women receiving NACT followed by hysterectomy increased from 11.6% to 21.7% (adjusted-odds ratio [aOR] per year: 1.12, 95% CI: 1.08-1.16, p<0.001), whereas those undergoing primary surgery followed by chemotherapy decreased from 62.7% to 48.3% (p<0.001). The number of women receiving chemotherapy alone was unchanged from 25.7% to 30.0% (p=0.199). In multivariable analysis, women in the NACT followed by hysterectomy group had an overall survival comparable to those in the primary hysterectomy followed by chemotherapy group (median: 25 vs 26 months, adjusted HR [aHR]: 1.03, 95% CI: 0.93-1.15, p=0.528) whereas those who received chemotherapy alone without hysterectomy had decreased overall survival (median 9 vs 26 months, aHR 2.56, 95% CI: 2.32-2.81, p<0.001). When restricted to those without distant organ metastasis (n=3,558), the increasing trend of NACT (9.3% to 25.5%, aOR per year: 1.15, 95% CI: 1.10-1.19, p<0.001) and decreasing trend of primary surgery followed by chemotherapy (78.0% to 58.2%, p<0.001) remained robust. However, in this subgroup, NACT followed by hysterectomy was associated with decreased overall survival compared to primary hysterectomy followed by chemotherapy (median: 25 vs 28 months, aHR: 1.20, 95% CI: 1.05-1.36, p=0.007). Conclusions: This study suggests a treatment shift from primary surgery to NACT in stage IVB endometrial cancer in the United States. Survival effects of a NACT-based treatment approach for metastatic endometrial cancer merit further investigation. Objectives: The role of neoadjuvant chemotherapy (NACT) in advanced endometrial cancer is currently under active investigation. This study examined the trends, characteristics, and outcomes of women with stage IVB endometrial cancer who received NACT prior to hysterectomy. Methods: This retrospective observational study queried the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program. The study population included 5,505 women with stage IVB endometrial cancer from 2010-2018. The exposure allocation was per treatment approach: primary hysterectomy followed by chemotherapy (n=3,052, 55.4%), NACT followed by hysterectomy (n=930, 16.9%), and chemotherapy alone without hysterectomy (n=1,523, 27.7%). The main outcome measures were (i) trend of utilization and patient characteristics related to NACT assessed with multinomial regression analysis and (ii) all-cause mortality per treatment approach assessed with multivariable Cox proportional hazards regression model. Results: Sites of distant organ metastasis included lung (23.9%), liver (11.9%), bone (7.6%), and brain (1.8%). The number of women receiving NACT followed by hysterectomy increased from 11.6% to 21.7% (adjusted-odds ratio [aOR] per year: 1.12, 95% CI: 1.08-1.16, p<0.001), whereas those undergoing primary surgery followed by chemotherapy decreased from 62.7% to 48.3% (p<0.001). The number of women receiving chemotherapy alone was unchanged from 25.7% to 30.0% (p=0.199). In multivariable analysis, women in the NACT followed by hysterectomy group had an overall survival comparable to those in the primary hysterectomy followed by chemotherapy group (median: 25 vs 26 months, adjusted HR [aHR]: 1.03, 95% CI: 0.93-1.15, p=0.528) whereas those who received chemotherapy alone without hysterectomy had decreased overall survival (median 9 vs 26 months, aHR 2.56, 95% CI: 2.32-2.81, p<0.001). When restricted to those without distant organ metastasis (n=3,558), the increasing trend of NACT (9.3% to 25.5%, aOR per year: 1.15, 95% CI: 1.10-1.19, p<0.001) and decreasing trend of primary surgery followed by chemotherapy (78.0% to 58.2%, p<0.001) remained robust. However, in this subgroup, NACT followed by hysterectomy was associated with decreased overall survival compared to primary hysterectomy followed by chemotherapy (median: 25 vs 28 months, aHR: 1.20, 95% CI: 1.05-1.36, p=0.007). Conclusions: This study suggests a treatment shift from primary surgery to NACT in stage IVB endometrial cancer in the United States. Survival effects of a NACT-based treatment approach for metastatic endometrial cancer merit further investigation.